Using taskfs from Linux.

The plan9port is allowing using synthetic inferno filesystems from Linux systems. I have used this to simplify testing of inferno setup. This blog will explain how this test-setup is created.

Firstly, you will need to install plan9port by downloading plan9port.tgz. Detailed installation instructions are available here , but I will repeat here what I have done for this.

mkdir for_plan9
cd for_plan9
wget http://swtch.com/plan9port/plan9port.tgz
tar -xvf plan9Port.tgz
cd plan9
./INSTALL

You will need to add few paths related to plan9port to your path. Once that is done, you can mount exported inferno filesystem using 9pfuse. Once mounted, these files can be manipulated using simple linux tools. For unmounting these filesystem you can use fusermount with -u option.

Now, for test purposes, I have two inferno instances running on inferno-test host using separate port numbers, and one is running locally. For automatically mounting these remote ends and export local taskfs startup script of inferno is used. This startup script option works well with Linux emu, but may not work on other platform, so check before using. It can be used as emu -v . Following is the script which starts my inferno with taskfs.

$ cat runInfernoScript.sh 
#!/bin/bash
BASEDIR=/home/pravin/projects/inferno/pravin/
INSTALL_DIR=inferno-rtasks
$BASEDIR/$INSTALL_DIR/Linux/386/bin/emu -r $BASEDIR/$INSTALL_DIR/  -v /dis/sh.dis /dis/rmount.sh

here, /dis/sh.dis is responsible for inferno shell and /dis/rmount.sh is my script which does all the initialization I need. Here is the content of it.

echo exporting /task
styxlisten -A tcp!*!5555 export /task
echo Mounting 6666 on host1
mount -A tcp!9.3.61.180!6666 /remote/host1
echo Mounting 6667 on host2
mount -A tcp!9.3.61.180!6667 /remote/host2
echo Mounting from localhost:6666 on host3
mount -A tcp!127.0.0.1!6669 /remote/host3
echo Mounting from localhost:6667 on host4
mount -A tcp!127.0.0.1!6670 /remote/host4
pause # this will stop emu from quiting immediately.
echo You should never see this line in output.

Command pause on second last line makes sure that emu will not terminate after executing startup script.

Now, lets go to Linux shell, and execute following script.

#!/bin/bash
set -e
cmd='hostname'
9pfuse localhost:5555 mpoint
cd mpoint/remote
res=`cat clone`
echo "Taskfs resource allocated is $res" 
cd $res
echo res 4 > ctl
echo exec $cmd > ctl
echo "Showing output bellow --------------------"
cat stdio

echo "Showing stderr bellow --------------------"
cat stderr


echo "Showing status bellow --------------------"
cat status

cd ..
cd ..
cd ..
fusermount -u mpoint
echo "done -------------------------------------"

Above code does following.

Mount taskfs using 9pfuse.
Reserve 4 remote resources.
Execute hostname command on them.
Get the output from stdio.
Show any errors from stderr.
Show the information related to the status of all remote nodes.
Release taskfs by unmounting it using fusermount.

And here is the output of running this script.

$ ./testRun.sh 
Taskfs resource allocated is 0
Showing output bellow --------------------
inferno-test
BlackPearl
inferno-test
inferno-test
Showing stderr bellow --------------------
Showing status bellow --------------------
cmd/0 5 Done /home/pravin/inferno/host2//ericvh-brasil/ hostname
cmd/1 5 Done /home/pravin/projects/inferno/ericvh//ericvh-brasil/ hostname
cmd/1 5 Done /home/pravin/inferno/ericvh//ericvh-brasil/ hostname
cmd/1 5 Done /home/pravin/inferno/host2//ericvh-brasil/ hostname
done -------------------------------------

You can see from the output that, out of 4 remote resources requested, 3 requests went to two inferno instances running on same host and one was allocated to single inferno instance running on other host. Only one instance was used twice, all other inferno instances were used only once.

So, this is first working proof that taskfs can be used to distribute jobs to multiple nocdes. And this can be done simply by mounting taskfs and using it directly.